1. Field of Invention
This invention is generally related to flashlights and is more specifically directed to flashlights that can be attached to implements such as law enforcement batons or nightsticks. The invention is most specifically directed to a flashlight that incorporates circuit boards as electrical components, an adjustable focus that cannot be inadvertently altered, and a switch that is positioned to enhance ease of use particularly in law enforcement situations.
2. Description of the Prior Art
Flashlights are well known in the prior art and have been heavily utilized in emergency situations and by law enforcement personnel in the execution of their duties. During use, such flashlights may be subjected to harsh environments and treatment, and therefore should be designed to withstand the application of various forces, whether rolling around under the seat of a car or blocking blows from suspects, as well as the presence of debris, including water and mud, that could interfere with the operation of the flashlight. Generally, such flashlights include a housing which is formed of a body section and a head section. The head section typically is disposed to receive a lens, a reflector, and a lamp, all of which are secured in the head by a lens ring that is threadingly engaged with the head section. The body section houses batteries utilized to energize the lamp.
The electrical circuit of such flashlights is typically comprised of a first wire or metallic strip that connects the positive terminal of the battery with the positive lead of the lamp, and a second wire or metallic strip that connects the negative terminal of the battery with the negative lead of the lamp. The second wire may be attached to an electrically conductive spring that contacts the negative terminal of the battery while urging the positive terminal of the battery into contact with the first wire. In some prior art embodiments, the second wire is attached directly to the flashlight housing or barrel such that the circuit is completed utilizing the housing itself as a conductor, the housing also being attached to the conductive spring.
To control operation of the lamp, a switch is disposed within the circuit. There are numerous varieties of switches that are utilized in the prior art to open and close a circuit. These switches are generally either mechanical or electrical. One common variety is a slide switch that mounts on the forward body section of the flashlight and utilizes a metallic strip to bridge a gap created in the wiring on the negative side of the electrical system. The switch includes a slide member that mounts in a slot on the external surface of the body section. The slide member can be used to move the metallic strip between a first "off" position in which the metallic strip is insulated from contact with the negative side of the electrical system and a second "on" position in which the metallic strip bridges the gap in the circuit, closing the circuit to activate the flashlight lamp.
Another type of switch simply replaces the slide switch with a forward mounted, push-button switch that can be activated to open and close a circuit. Push-button switches, whether mechanical or electrical, are well known in the art and are generally characterized by a distinctive "click" as the switch is engaged and disengaged. In the case of mechanical push-button switches, this "click" is generated as metallic parts within the switch strike one another. In other instances, such as in electrical pushbutton switches, the "click" emanates from the depression and release of a spring mechanism or catch mechanism within the switch. In any event, such switches are undesirable because the distinctive "click" could be used by suspects or those under surveillance to identify the presence or location of law enforcement personnel.
Push button switches are also commonly used as "dead man" switches. In law enforcement, it is often desirable to utilize a switch that only maintains electrical contact when the switch is depressed and manually held down by the user. Upon release of the button, the electrical circuit is interrupted. Thus if the flashlight falls from the user's hand, the circuit is broken and the flashlight is extinguished. For example, if a police officer becomes injured or incapacitated in such a way as to drop his or her flashlight, a deadman switch will cause the flashlight to extinguish, preventing a suspect from ascertaining the injured officer's location. Another common use of such a switch is to permit intermittent use of a flashlight, such as for signalling purposes. In any event, like the other prior art push button-type switches, dead man switches are characterized by a distinctive "click" as the switch is engaged and disengaged.
Although push button switches are generally more reliable than slide switches, push button switches are susceptible to damage from exposure to moisture or particulate matter such as dust or dirt. Therefore, push button switches incorporated into flashlights are often covered to inhibit migration of moisture and debris into the switch. The covering is usually some type of thin, resilient membrane such as rubber or the like and may take several different forms. For example, MAGLITE, a well known flashlight manufacturer, provides a bowl shaped cover with a thin lip around the open end of the cover. The cover also has an aperture or slit in the center of the bowl. To "seal" the cover over the switch, the cover is placed over the switch so that the lip is sandwiched between an inner portion and an outer portion of the flashlight. An allen wrench is then inserted through the slit to engage a threaded fastener attaching the inner and outer portions. The threaded fastener is then rotated to draw the inner and outer portions together such that the lip of the switch cover is tightly sandwiched between the inner and outer portions. Clearly, although the outer perimeter of the switch cover is sealed, the slit in the bowl of the switch cover still renders the switch cover penetrable by moisture and debris.
Another type of switch used in the prior art flashlights utilizes the flashlight housing as a portion of the negative side of the electrical circuit. Typically, these types of flashlights require rotation of one portion of the flashlight body relative to another portion of the flashlight body to open and close the circuit. The head of the flashlight must be rotated relative to the body of the flashlight to activate and deactivate the flashlight lamp. In such a configuration, the negative lead from the lamp is attached to the flashlight head, while the negative terminal from the battery is attached to the flashlight body. The body and the head are threadingly engaged to permit rotation of the head relative to the body. When assembled, the head and body are insulated from one another to preclude electrical contact. Only upon additional rotation of the head towards the body is electrical contact between conductive portions of the two sections achieved such that the negative circuit is closed.
In another similar type of switch, a flashlight is provided with an endcap that can be rotated relative to the body of the flashlight to close the negative side of the electrical circuit. The endcap is in electrical contact with the negative terminal of a battery and is threadingly engaged with the flashlight body. However, the endcap is insulated from electrical contact with the body itself such that the conductive portions of the body and endcap are not in contact. Only upon rotation of the endcap relative to the body are the electrically conductive portions of the endcap and body brought together to close the circuit and activate the flashlight lamp. An example of such a flashlight is manufactured by Laser Products, and further includes a mechanical deadman switch positioned on side of the endcap.
Switches such as the above-mentioned push-button type and slide type are typically mounted at the forward end of the flashlight near the head portion of the body. More specifically, such switches at or forward of the center of gravity of the flashlight because the most common activation finger, the thumb, naturally rests at this point. Flashlights are most often supported in the "underhand" position by resting the barrel of the flashlight on the fingers and closing the palm of the hand around the side of the barrel such that the thumb is disposed on the top of the barrel and points forward, away from the user. This position enhances the balance of the flashlight in the fingers and palm of a user's hand while permitting the user to easily activate and deactivate the switch with the forward pointed thumb. With such a grip, the "ready" position of the light is comfortably between the waist and chest.
Law enforcement personnel more commonly support flashlights in the "overhand" position that permits the light to be most comfortably held at shoulder level or higher. Specifically, this position entails resting the barrel of the flashlight in the palm of the hand and closing the fingers around the side and over the top of the barrel. In this position, the thumb is disposed on the bottom of the barrel and points backward, toward the user. With the thumb in this position, a forward mounted switch would be difficult to operate. Therefore, placement of the prior art switches is not conducive to use by law enforcement personnel who are often required to hold the flashlight in a specific "maneuver" position or in combination with other instruments.
One common problem with the push-button type and slide type switches of the prior art is that they are not typically provided with a "back-up" system or method for ensuring that the flashlight will continue to function should a portion of the switch fail. For example, it is typical for the metallic strip of the slide type switch to become loose over time, unintentionally interrupting the electrical contact between the metallic strip and the wires of the circuit. The result of such an interruption is failure of circuit and hence failure of the flashlight. Failure of the flashlight, especially in emergency or law enforcement situations, is undesirable at best and could place the flashlight user in jeopardy.
Notwithstanding the manner is which prior art flashlights are activated, such flashlights are typically pre-focused at the factory to provide a light beam that is a combination of a spot light and a flood light. Spot lights are characterized by a narrow, intense beam of light that projects over a distance, while flood lights are characterized by a broad, diffused beam of light that illuminates the immediate area around the light. The nature of a particular beam of light is determined by the light focal length (LFL), which is the distance between the light bulb filament and the base of the parabolic reflector. The greater the LFL, the more diffused the light beam. In other words, a flood light has a larger LFL than a spot light.
In any event, most prior art flashlights are pre-set at the factory to have a light beam that is a combination flood and spot. The position of the light bulb relative to the reflector is permanently fixed at the factory to achieve this combination. One problem with such flashlights is that the position of the filament from light bulb to light bulb is not exact. Thus the LFL for a flashlight can vary depending on the particular light bulb inserted into the flashlight.
More recent prior art flashlights have been focusable. Focusable flashlights permit the user to select the type of beam to be generated--either flood, spot or a combination--depending on the user's particular requirements. Focusable flashlights are typically adjusted by turning the head of the flashlight relative to the body of the flashlight. The reflector is attached to the head of the flashlight while the light bulb is attached to the body of the flashlight. Since the head of the flashlight is threadingly attached to the body of the flashlight, rotation of the head of the flashlight relative to the body alters the LFL, permitting a user to achieve the desired beam of light. One drawback to a focusable flashlight is that the relative position of the body and the head of the flashlight can be altered inadvertently, especially when the threads attaching the head to the body become worn or loose.
Flashlights used in law enforcement or emergency situations are often subject to harsh environments and treatment. A blow to the outside of a focusable prior art flashlight has a tendency to knock the flashlight out of focus. The same is true for flashlights that may be left to roll around in a vehicle--the head of the flashlight may have a tendency to move relative to the body of the flashlight. Clearly, there are many instances in which a flashlight focusable by rotating the head relative to the body can be inadvertently altered. In such instances, the focus of the flashlight must be re-set each time the flashlight is used, consuming valuable time and frustrating to the user.
Another drawback to prior art flashlights, especially those subject to harsh treatment, is that the flashlights may not sufficiently insulate the lamp bulb from external shocks placed on the flashlight. Flashlight bulbs are generally provided with a positive and negative pin extending from the end of the lamp bulb. In prior art flashlights, typically, the bulb is cantilevered on the two conducting pins of the lamp bulb such that the glass end, the most fragile portion of a lamp bulb, is unsupported. External blows placed on the flashlight or sudden movements of the flashlight can result in damage to an unsupported lamp bulb. This is especially true since the cantilevered nature of the prior art lamp bulbs has a tendency to magnify forces transferred to the glass body of the bulb through the attachment pins.
Based on the prior art flashlights, therefore, it would be desirable to provide a law enforcement flashlight that is reliable while being suited to withstand the rigorous treatment and environments common to law enforcement. As such, not only should the electrical circuit be reliable, but the lamp bulb and lamp switch should be protected from damage as well. In addition, the focus of the flashlight should be adjustable and adaptable to suit the particular situation in which it is utilized, yet should remain tightly focused even when the flashlight is subjected to external forces. The flashlight should be comfortable to hold and easily operable, yet should be configured to minimize revealing the presence or location of the user. Finally, the flashlight should also be adaptable for use with other law enforcement tools, such as an ASP expandable baton.